The Chilcatay Formation is a geologic formation located in Peru. The formation was deposited in the Pisco Basin, during the Early Miocene, roughly from 19.2 to 18.0 Ma. Fossil remains of baleen whales, sharks, and rays have been found in the formation.
Paleobiota of the Chilcatay Formation
Mammals
Dolphins
Taxa Species Material Description Images Notes Huaridelphis H. raimondii A squalodelphinid river dolphin Ensidelphis E. riveroi A river dolphin Furcacetus F. flexirostrum A river dolphin Incacetus I. broggii A kentriodontid dolphin cf. Kentriodon cf. K. sp. A kentriodontid dolphin Macrosqualodelphis M. ukupachai A squalodelphinid river dolphin Notocetus N. vanbenedeni A squalodelphinid river dolphin Squalodelphinidae Gen. et. sp. indet. A river dolphin
Whales
Taxa Species Material Description Images NotesAmphidelphis A. bakersfieldensis A cranium Lambert, O.; de Muizon, C.; Bennion, R. F.; Urbina, M.; Bianucci, G. (2025). "New data on archaic homodont odontocetes from the Early Miocene of Peru reveal a second species of Chilcacetus Lambert, Muizon & Bianucci, 2015 and a Southern Hemisphere record for a northeastern Pacific species". Geodiversitas. 47 (9): 369–408. doi:10.5252/geodiversitas2025v47a9. Cetotheriidae Gen. et. sp. indet. Chaeomysticeti Gen. et. sp. indet.A partial skull (CTZ 02) A baleen whale; either a late-diverging stem mysticete or an early-branching crown mysticeteA badly damaged dentary (ZM 98)A baleen whale; crownward of EomysticetidaeA skull (ZM 152)A crown-group baleen whale, possibly a basal plicogulan Chilcacetus C. cavirhinus A toothed whale C. ullujayensis Diaphorocetus D. otergai A physeteroid sperm whale Eurhinodelphinidae Gen. et. sp. indet. A toothed whale Inticetus I. vertizi A toothed whale Mysticeti Gen. et. sp. indet. A baleen whale Odontoceti Gen. et. sp. indet. A toothed whale Rhaphicetus R. valenciae A physeteroid sperm whale
Seals Taxa Species Material Description Images Notes Pinnipedia Gen. et. sp. indet. A seal
Birds
Penguins
Taxa SpeciesMaterial Description Images Notes Palaeospheniscus P. sp. An early penguin
Reptiles Turtles
Taxa SpeciesMaterial Description Images Notes Testudines Gen. et. sp. indet. A turtle
Crocodilians
Taxa Species Material Description Images Notes Sacacosuchus S. cordovai A gavialid crocodilian
Cartilaginous fish
Rays
Taxa Species Material Description Images Notescf. Anoxypristiscf. A. sp.A rostral spineA sawfish Dasyatidae Gen. et. sp. indet.Dermal denticles A whiptail stingrayMyliobatoideaGen. et. sp. indet.TeethA stingray; several of the teeth compare favorably with Myliobatis eagle rays
Sharks
Taxa Species Material Description Images NotesAlopiasA. superciliosusTeethThe bigeye thresherA. cf. vulpinusTeethTentatively assigned to the common thresherAnotodusA. agassiziiTeethA thresher sharkCarcharhinusC. brachyurusTeethThe copper sharkC. dicelmaiC. cf. leucasA toothTentatively assigned to the bull sharkCarchariasC. sp.TeethA sand tiger sharkCarcharodonC. subauriculatusJunior synonym of C. chubutensis and C. megalodon.CosmopolitodusC. hastalisTeethWhite sharksC. plicatilisTeethGaleocerdoG. aduncusTeethA tiger sharkHemipristisH. serraTeethA weasel sharkIsurusI. oxyrinchusTeethThe shortfin mako sharkMegalolamnaM. paradoxodonA toothA megatoothed sharkMegachasmaM. cf. applegateiTeethA megamouth sharkNegaprionN. brevirostrisTeethThe lemon sharkOtodusO. chubutensisTeethA megatoothed shark; sometimes placed in separate genus CarcharoclesParotodusP. benedeniiTeethA possible megatoothed sharkPhysogaleusP. contortusTeethA ground sharkSphyrnaS. zygaenaTeethThe smooth hammerhead Squatina S. sp.Teeth An angel shark
References